KABUL, Afghanistan - Bombings across Afghanistan killed two American troops and six civilians Monday, authorities said, as the death toll in the country's deadliest insurgent attack this year rose to at least 50.
The attacks, including Sunday's mass killing by a suicide bomber at a volleyball tournament, come amid a renewed Taliban offensive as foreign troops begin to withdraw from the country.
In a statement, NATO said the troops had been killed by an "enemy attack in eastern Afghanistan." CBS News correspondent David Martin reports sources say they were both Americans.
A spokesman for Kabul's police chief, Hashmat Stanekzai, said the troops were killed when a bomb attached to a bicycle exploded near a foreign military convoy in the eastern part of the capital Monday morning. He said the blast wounded one Afghan civilian.
A total of 63 NATO troops have been killed this year, at least 46 of them Americans.
Another bomb attached to a motorcycle exploded later Monday in a crowded market in Afghanistan's northern Kunduz province, killing six people and wounding at least five, police spokesman Sarwar Hussaini said.
No group claimed responsibility for either attack Monday. Insurgents have stepped up their assaults against Afghan security forces in a bid to undermine the Western-backed Kabul government of President Ashraf Ghani.
The insurgents' deadliest attack this year, the volleyball tournament bombing Sunday in Paktika province bordering Pakistan, killed at least 50 people, said Mokhlis Afghan, a spokesman for the provincial governor. He said authorities were still trying to determine an accurate death toll Monday.
The suicide bomber detonated explosives as he mingled with the large crowd there, causing the many casualties. Interior Ministry spokesman Seddiq Sediqqi said the dead included 10 members of a local police force, including a police commander.
Abdullah Abdullah, the country's chief executive, visited a hospital in Paktika province Monday to see the wounded. He said locals believed the Taliban carried out the attack as they opposed the insurgents.
"They were saying that the local police should be strengthened," Abdullah said. "I promised them I'd make it a priority."